1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '43b66170c341d01cdde74f5a1a4220a3', '3.149.214.144', '1722054303', '1722054303', '/shop_content.php/coID/7/content/Kontakt')

[XT SQL Error]